Hummer H2. Manual - part 1651

DTC P0327 OR P0332 

Circuit Description 

The knock sensors (KS) produce an AC signal under all engine operating conditions. When the engine is 
running, the powertrain control module (PCM) learns a minimum and maximum frequency of normal engine 
noise. The KS system monitors both knock sensors in order to determine if knock is present. If the KS system 
determines that excessive knock is present, the PCM retards the spark timing based on the signals from the KS. 
The PCM continues to retard timing until no knock is present. If the PCM detects that the frequency is out of 
the normal range, DTC P0327 or P0332 will set. 

Conditions for Running the DTC 

z

DTCs P0116, P0117, P0118, P0122, P0123, P0125, or P0128 are not set.  

z

The minimum noise level must be learned. The minimum noise level is learned when the following 
conditions are met: 

{

The engine coolant temperature (ECT) is more than 60°C (140°F).  

{

The engine RPM is between 475-975 for 10 seconds.  

z

The engine speed is between 1,500-3,000 RPM.  

z

The manifold absolute pressure (MAP) is less than 45 kPa.  

z

The engine run time is more than 10 seconds.  

z

The ignition voltage is more than 10 volts. 

2

3. Start the engine.  

4. Operate the vehicle within the Conditions for 

Running the DTC. You may also operate the 
vehicle within the conditions that you observed 
from the Freeze Frame/Failure Records.  

Did the DTC fail this ignition?

Go to Step 3

Go to Intermittent 

Conditions

3

Replace the PCM. Refer to Powertrain Control 
Module (PCM) Replacement . 
Did you complete the replacement?

Go to Step 4

-

4

1. Start the engine.  

2. Operate the vehicle within the conditions for 

Running the DTC. You may also operate the 
vehicle within the conditions that you observed 
from the Freeze Frame/Failure Records.  

Did the DTC fail this ignition?

Go to Step 2

Go to Step 5

5

Observe the Capture Info with a scan tool. 
Are there any DTCs that have not been diagnosed?

Go to Diagnostic 

Trouble Code 

(DTC) List

System OK

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and 

6.0L - Hummer H2

  

Conditions for Setting the DTC 

The PCM detects that the affected KS signal is less than the expected amount for more than 9 seconds. 

Action Taken When the DTC Sets 

z

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition 
cycle that the diagnostic runs and fails.  

z

The control module records the operating conditions at the time the diagnostic fails. The first time the 
diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 
reports a failure on the second consecutive ignition cycle, the control module records the operating 
conditions at the time of the failure. The control module writes the operating conditions to the Freeze 
Frame and updates the Failure Records.  

Conditions for Clearing the MIL/DTC 

z

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles 
that the diagnostic runs and does not fail.  

z

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.  

z

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other 
emission related diagnostic.  

z

Clear the MIL and the DTC with a scan tool.  

Diagnostic Aids 

z

Inspect the KS for proper installation. A knock sensor that is loose or over torqued may cause the DTC to 
set.  

z

If DTCs P0327 and P0332 are set at the same time, inspect for poor connections at the KS harness 
jumper, located at the left rear side of the intake manifold.  

z

For an intermittent, refer to Intermittent Conditions .  

DTC P0327 or P0332 

IMPORTANT: If the KS is dropped, the sensor must be replaced.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics 
Connector End View Reference: Engine Controls Component Views or Powertrain Control 
Module (PCM) Connector End Views

1

Did you perform the Diagnostic System Check-
Engine Controls?

-

Go to Step 2

Go to Diagnostic 

System Check - 

Engine Controls

IMPORTANT:

If an engine knock can be heard, repair the engine 
mechanical condition before proceeding with this 
diagnostic.

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and 

6.0L - Hummer H2

  

2

1. Observe the Freeze Frame/Failure Records for 

this DTC.  

2. Turn OFF the ignition for 30 seconds.  

3. Start the engine.  

4. Operate the engine within the Conditions for 

Running the DTC. You may also operate the 
vehicle within the conditions that you observed 
from the Freeze Frame/Failure Records.  

Did the DTC fail this ignition?

-

Go to Step 3

Go to Diagnostic 

Aids

3

1. Turn OFF the ignition  

2. Remove the intake manifold sight shield. Refer 

to Engine Sight Shield Replacement (6.0L 
(LQ4)) in Engine Mechanical.  

3. Disconnect the knock sensor (KS) inline 

harness connector.  

4. Measure the resistance from the signal circuit 

of the affected KS to a good ground with a 
DMM.  

Is the resistance of the KS within the specified range?

93K-

107K 

ohm

Go to Step 4

Go to Step 6

4

1. Measure the AC voltage from the signal circuit 

of the affected KS to a good ground.  

2. Tap on the engine block near the affected KS 

while observing the DMM.  

Does the voltage change on the DMM while tapping 
on the engine block near the KS?

IMPORTANT:

Do not tap on any plastic engine components.

-

Go to Step 5

Go to Step 10

5

Test the affected KS signal circuit between the PCM 
and the KS inline harness connector for the following 
conditions: 

z

An open or a high resistance  

z

A short to voltage  

z

A short to ground  

 
Refer to Circuit Testing and Wiring Repairs in 
Wiring Systems. 

-

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and 

6.0L - Hummer H2

  

Did you find and correct the condition?

Go to Step 12

Go to Step 8

6

1. Remove the intake manifold. Refer to Intake 

Manifold Replacement in Engine Mechanical. 

2. Test the affected signal circuit between the KS 

inline harness connector and the affected KS 
connector for an open, high resistance or short 
to ground. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems.  

Did you find and correct the condition?

-

Go to Step 12

Go to Step 7

7

Test for an intermittent and for a poor connection at 
the affected KS. Refer to Testing for Intermittent 
Conditions and Poor Connections and Connector 
Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 10

8

Test for an intermittent and for a poor connection at 
the KS inline harness connector. Refer to Testing for 
Intermittent Conditions and Poor Connections and 
Connector Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 9

9

Test for an intermittent and for a poor connection at 
the PCM. Refer to Testing for Intermittent 
Conditions and Poor Connections and Connector 
Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 11

10

Replace the affected knock sensor. Refer to Knock 
Sensor (KS) Replacement . 
Did you complete the replacement?

-

Go to Step 12

-

11

Replace the PCM. Refer to Powertrain Control 
Module (PCM) Replacement . 
Did you complete the replacement?

-

Go to Step 12

-

12

1. Clear the DTCs with a scan tool.  

2. Turn OFF the ignition for 30 seconds.  

3. Start the engine.  

4. Operate the vehicle within the Conditions for 

Running the DTC as specified in the 
supporting text. You may also operate the 
vehicle within the Freeze Frame/Failure 
Records.  

Did the DTC fail this ignition?

-

Go to Step 2

Go to Step 13

13

Observe the Capture Info with a scan tool. 
Are there any DTCs that have not been diagnosed?

-

Go to 

Diagnostic 

Trouble Code 

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and 

6.0L - Hummer H2